st: error message when using gllamm "insufficient observations"

hello statalisters,
i am trying to use -gllamm- to do a 2 stage endogenous system where one stage is a survival estimation. before i attempt this, i thought i would try to run a simple one stage poisson regression using -gllamm- to compare it to a stcox to make sure i am doing it correctly. but i keep getting an error message of "insufficient observations" when trying to run -gllamm-. any ideas (other than the obvious) about why this might be occurring? i am wondering if there is something about the clustering that i haven't done properly. here is the code:
gllamm6 speed lr_size , family(poisson) i(licensor_numb)
here are the stats on the clustering variable:
. sum licensor_numb
Variable | Obs Mean Std. Dev. Min Max
-------------+--------------------------------------------------------
licensor_n~b | 157 40.18471 24.24417 1 84
karen.
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